Window periods

Published: 30 June 2012

With one exception, all the currently available rapid tests look for antibodies only, which means that their window periods are at least as long as those of third-generation tests. (As described above, this is estimated to be between three and six weeks.)

However, when tested against blood samples of people during seroconversion, rapid tests have tended to detect infection a few days later than conventional third-generation tests.1

Moreover comparison tests between different rapid tests often show a wide range in performance.2345 Details from these evaluations, when available, are described in the section on accuracy, below.

Although a rapid test which can detect both antibodies
and p24 antigen was introduced in 2009 (Determine HIV-1/2 Ag/Ab Combo), the
test’s window period does not appear to be as short as that of laboratory
fourth-generation tests.

If the result of a rapid test is non-reactive but there has been a recent high-risk exposure, some testing sites may take a blood sample for laboratory analysis with a fourth-generation test.

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends
checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member
of your healthcare team for advice tailored to your situation.